There is an wide range and variety of information available on the Internet, with a wide range of accuracy, reliability, and value. Unlike most traditional information sources (books, magazines, etc.), no one has to evaluate or approve Internet content before it is made public. Basically, anybody with a computer can put anything he wants onto the Internet. It is your job as a researcher, therefore, to evaluate what you locate, in order to determine whether it suits your needs.

The CARS (Credibility, Accuracy, Reasonableness, Support) Checklist is designed to assist researchers in evaluating information sources. Few sources will meet every single criterion on this list, but if you learn to use and apply these criteria, you will be better able to separate the high quality information from the poor quality information as you do your research.


Because people have always made important decisions based on information, evidence of authenticity and reliability—or credibility, believability—has always been important. If you read an article saying that the area where you live will experience a major earthquake in the next six months, it is important that you should know whether or not to believe the information. Credibility is a measure of the authenticity or reliability of the source of information. To determine credibility you may ask: Why should I believe this sources of information over another? How does this source know this information. What is it about this source makes it believable (or not)?

Indicators of credibility:

  • An author’s credentials—his or her training and education in a field relevant to the information. Look for the author’s degree or title or position of employment. Does the author provide contact information (email or snail mail address, phone number)? If the source of the information is an organization or group, ask yourself if it is a respected body (i.e., the Mayo Clinic, the American Dental Association, the psychology department at Harvard University).
  • Evidence of quality control—most scholarly information passes through a process of peer review, whereby several experts within that field of study review the author’s writings to ensure that his or her conclusions are valid and in keeping with current knowledge in the field. Journals of this type are known as academic, or scholarly, or refereed publications, and they are available both online and in print formats. Information presented on organizational websites is also generally peer-reviewed, since it is issued in the name of an organization (the American Psychological Association, for example).

Indicators of a possible lack of credibility:

  • Anonymity (no author listed)—why is the author hiding?
  • A lack of quality control (see explanation above).
  • Poor visual presentation of information—credible authors/websites present their information in a well-organized and professional manner. If the website is poorly designed and put together (clashing combinations of color, difficult-to-read fonts, page navigation hard to understand), this can be an indicator that the information is less than credible.
  • Bad grammar and/or misspelled words. Educated people use grammar fairly well and check their work for spelling errors. An occasional error is not unusual, but more than two or three spelling or grammar errors is cause for caution at least. Whether the errors resulted from carelessness or ignorance, neither puts the information or the writer in a favorable light.


The goal of the accuracy test is to ensure that the information is actually correct: up to date, detailed, exact, and comprehensive. Keep in mind that something that was true twenty years ago may no longer be true today (this is especially true in fast-changing fields, like medicine and technology). Or, a reputable source might be giving you up-to-date information, but the information is only partial and not the full story. The more information you have on a subject, the better able you will be to make an informed judgment as to a source's accuracy.

Indicators of accuracy:

  • Timeliness—this is a measure of how “up-to-date” information is. In many disciplines (i.e., the sciences, medicine, technology), timeliness is a very important measure of the relevance of information, and therefore, its accuracy, since new discoveries are constantly being made and "the facts" about that subject are constantly changing. You need to be careful to note when the information you find was created, and then decide whether it is still of value. Old information is not necessarily bad: nineteenth-century American history books or literary anthologies can be highly educational when compared with what is being written or anthologized now. And some work is timeless, such as the philosophical work of Aristotle and Plato, or the original psychological theories of Sigmund Freud. In many cases, though, you will want only the most accurate and up-to-date information you can find.
  • Comprehensiveness—the ideal article or website presents a thorough discussion of the subject, as opposed to only "touching on the highlights." No one can read 20,000 articles on the same subject before coming to a conclusion or making a decision. And no single piece of information will offer a truly complete story. That's why we rely on more than one source and why we try to find a variety of sources in different formats (book, scholarly journal article, material from an online database, etc.).
  • Lack of a bias—by addressing all sides of an issue, the author ensures that you have a complete and objective treatment of the topic. Biased information is not completely useless, but the bias must be taken into consideration when you interpret and use the information.

Indicators of a possible lack of accuracy:

  • A source that deliberately leaves out important facts, qualifications, consequences, or alternatives, may be misleading or even intentionally deceptive.
  • Vague or sweeping generalizations—as opposed to exact facts and figures.
  • No date on the document, or a very old date on a document, particularly one containing time-sensitive information.
  • A very one-sided view that does not acknowledge opposing views or respond to them. For example, a gun rights website that promotes gun ownership and defends the 2nd Amendment, but does not address the societal problems stemming from gun violence. Information pretending to be objective but possessing a hidden agenda of persuasion or a hidden bias is among the most common kinds of information in our culture.


The measure of reasonable information lies in its fairness, objectivity, moderateness, and consistency.

Indicators of reasonableness:

  • Fairness—look for a balanced and well-reasoned argument. The tone of the article should be factual and thoughtful. A good information source will possess a calm, reasoned tone, arguing or presenting material thoughtfully and without attempting to get you emotionally worked up. Pay attention to the tone and be especially cautious of highly emotional writing.
  • Pure objectivity is almost impossible to find, but a good writer should be able to control his or her biases. You need to be aware that some individuals and organizations are naturally not neutral (the NRA, for example) and be on the lookout for slanted, biased, or politically-distorted work.
  • Moderateness—a test of the information against how the world really is. Use your own knowledge and experience to ask if the information is really likely, possible, or probable. Keep in mind that most information is ordinary and not likely to cause great excitement. If you find claims that are surprising or difficult to believe or which otherwise deviate from your own knowledge and experience, use caution and demand more
    evidence than you might require for a lesser claim. It is important to remember that some truths are in fact spectacular and immoderate. Don't automatically reject a claim or source simply because it is astonishing. Just be extra careful in checking it out.
  • Consistency—the facts and findings in an article (or website) should not contradict themselves in other parts of the same article (or website). Sometimes, when people spin falsehoods or distort the truth, inconsistencies or even contradictions show up.

Indicators of a possible lack of reasonableness:

  • A shrill or overly aggressive tone on the part of the author (i.e., referring to opponents as “stupid jerks” or belittling findings not in accordance with his own. Any time a writer puts him or herself in the way of the argument, either emotionally or because of self-interest, this often indicates a lack of reasonableness.
  • Overclaims—when the language is too grandiose or hyperbolic (i.e., "Thousands of children are murdered in this country every day" or "This is the most significant piece of medical research ever!" or "More than half of all Americans have had their cars stolen"). These sorts of statements are seldom, if ever, backed up with supporting evidence.
  • Sweeping generalizations—i.e., "It is obvious to everyone that…".
  • Data that contradicts itself.
  • Conflict of interest—"Welcome to the Old Stogie Tobacco Company Home Page. To read our report 'Cigarettes Make You Live Longer,' click here" or "The products our competitors make are dangerous and bad for your health."


Most information presented in an article comes from other sources. You need to ask yourself: where did this information come from? What sources did the information creator use? Is there a bibliography or other documentation? How does the writer know this? It is especially important that statistical information be documented. Otherwise, someone may be just making up numbers. By properly citing and acknowledging sources of information, an author strengthens his or her credibility.

Indicators of support:

  • Corroboration—do other sources agree with the information in this source? Corroboration or confirmability is an important test. Whether you're looking for a fact, an opinion, or some advice, it is a good idea to triangulate your findings. That is, find at least three sources that agree with each other. If your sources do not agree, you should do further research to find out the range of opinion or disagreement before you draw your own conclusions. What you are doing with corroboration, then, is using information to test information, finding information to support and reconfirm (or to challenge or rebut) information you've already found. Corroboration is especially important when you find dramatic or surprising information (information that fails the moderateness test, above).
  • External consistency—you also need to compare what is familiar in the new source with what is familiar in other sources. Where this source discusses facts or ideas I already know something about, does the source agree or harmonize with other sources, or does it conflict, exaggerate, or distort? The reasoning is that, if is a source is faulty where it discusses something you already know, it is likely to be faulty in areas you do not yet know, and you should therefore be cautious and skeptical about trusting it.
  • The claims made in the article are supported by facts and/or figures, the source of which is clearly noted.
  • Proper documentation and citing of the sources for facts and statistics used in the article. A bibliography or list of references or works cited at the end of the article (or website), for example.

Indicators of a possible lack of support:

  • Numbers or statistics are presented without an identified source for them.
  • Absence of source documentation when the discussion clearly calls for such documentation.
  • You cannot find any other sources that present the same information or acknowledge that the same information exists (lack of corroboration).
  • Claims are made by the author but are not supported with evidence.

(Source: Harris, Robert. “Evaluating Internet Research Sources.” 17 November 1997. VirtualSalt 26 June 2001.